Tray apparatus

ABSTRACT

Tray apparatus for receiving sheet material along a predetermined path and which lowers incrementally in response to a sensing circuit including a motor which lowers a tray member to maintain a constant level of the top sheet received with the sheet path. Two lamp and photodetector pairs serve to sense the level of sheet material received on the tray member and signifies when the tray member is to be lowered. The motor is reversible to return the tray member to its starting position for unloading the sheet material when full.

United States Patent Turner et al.

1541 TRAY APPARATUS [72] Inventors: H. Pittsford; Wil- Iiam P.Ktlklldtl, Henrietta, both Of [73] Assignee: Xerox Y Corporation,Stamford,

Conn.

221 Filed: Sept. 9, 1910 [21] Appl. No.: 70,734

52 us. (21., ..214/6 11, 271/88 I [51] Int. B653 57/03 [58] Field ofSearch...2l4/6 DS, 6 H, 6 DK, 6 P, 6 N, 214/6 D; 271/88, 86

[56] References cm UNlTED STATES PATENTS 2,928,559 3/ 1960 Moscly..214/6 H 3,303,942 2/ 1967 Thomas et al. ..214/6 P 3,374,902 3/ 1968Mills ..214/6 H 2,707,142 4/1955 Waite 8271/88 X 3,149,836 Ragozzino eta1 ..214/6 H 1451 Aug. 8, 1972 2,918,852 12/1959 Buccicone..'......214/6 N 3,369,675 2/1968 Buccicone ..214/6 11 3,583,614 6/1971Foster, Jr ..214/6 DS 2,875,908 3/1959 Woodcock", ..214/6 DK 2,639,8235/1953 Madden ..214/6 H 3,426,923 2/1969 Stegeman ..214/6 H PrimaryExaininer- -llobert A. Spar Attorney-James J. Ralabate, Norman E.Schrader and Melvin A. Klein I ABSTRACT Tray apparatus for receivingsheetmaterial along a predetermined path and which lowers incrementallyin full.

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PATENTEDAuc 81972 sum mar 10 0-004 JOFPZOO TRAY APPARATUS This inventionrelates to tray apparatus for receiving sheet material in booklet formor stacks and which lowers to maintain a level with the sheet path andraises to unload the sheet material.

As is well known in the art of bookrnaking, it is generally necessary tofirst print or copy sheets and then gather groups of difi'erent sheetsin a definite order referred to as collating. The operation of printingand then assembling sheets into booklets usually requires several steps,the last of which is taking one sheet from each of the stacks andputting these sheets together in the order desired.

Normally the assembling of the sheets into booklets by hand is slow andcumbersome. Also, the number of people necessary is considerable and thelikelihood of making a mistake great.

Present devices for mechanically assembling sheets into booklet formhave the disadvantage of being prolix and costly and have not beenentirely satisfactory.

The present invention enables automatic assembling of sheet materialinto separate identifiable stacks or booklets which may be fastenedintoa finished form.

To accomplish this, a tray apparatus accepts copy sheets from aprocessor in separated bundles and lowers in response to a level sensingcircuit until full and then raises to unload the sheets.

It is therefore an object of the present invention to improve theprinting of booklets.

It is another object of the present inventionv to stack collated sets ofcopy sheets from a processor in a manner more simple and cheaper thanheretofore.

It is another object of the present invention to collect copy sheetsfrom a processor into a tray capable of lowering to maintain a constantlevel with a sheet path in response to a level sensing circuit.

It is another object of the present invention to provide method andapparatus for stacking and unloading sheet material in a manner moreexpeditious than heretofore.

It is another object of the present invention to pro vide an elevatingtray apparatus which is simple and compact in design.

These objects as well as others will become more apparent uponconsidering the following description which is to be read in conjunctionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a copying machine incorporating afinishing apparatus according to the present invention;

FIG. 1a. is a view of the machine control panel section for thefinishing apparatus;

FIG. 2 is an isometric view of the exterior of the finishing apparatus;

FIG. 3 is a side sectional view of the finishing apparatus;

FIG. 4 is an end sectional view of the finishing apparatus;

FIGS. 4a c are end sectional views illustrating the various positionsfor the cover of the finishing apparatus;

FIG. 5 is a side view of the side stacking assembly;

FIG. 6 is a side view of the output receiving tray assembly illustratingdetails of the elevation control thereof; and

FIGS. 7,8 and 9 are diagrams of the control circuits of the finishingapparatus.

GENERAL an original to be reproduced is projected onto the sensitizedsurface of a xerographic plate to form an electrostatic latent image.Thereafter, the latent image is developed with toner material to form axerographic powder image corresponding to the latent image on the platesurface. The powder image is then electrostatically transferred to arecord material such as a sheet or web or paper or the like to which itmay be fused by a fusing device whereby the powder image is causedpermanently to adhere to the surface of the record materi- 'Ihexerographic processor indicated by the reference numeral 11 is arrangedas a self-contained unit having all of its processing stations locatedin a unitary enclosure or cabinet. The printer system includes anexposure station at which a light radiation pattern of a document to bereproduced is positioned on a glass platen 12 for projection onto aphotoconductive surface in the form of a xerographic belt 13. Thedocument is transported by a recirculating document feed apparatus 15from the bottom of a stack 17 on a supply tray 19 to the platen forexposure and then returned to the top of the supply tray on completionof the exposure until the entire stack has been copied at which time thecycle may be repeated as described in copending US. application Ser. No.781,287, filed on Dec. 4, 1968, entitled Document Feed Apparatus andcommonly assigned with the present invention.

Imaging light rays from the document as'fiash illuminated by lamps 18are projected by a first mirror 20 and a projection lens 21 and anothermirror 23 onto the belt 13 at the focal plane for the lens 21 at aposition indicated by the dotted line 25.

As an interface structure and for unobstructive optical projections, theside of the cabinet is formed with an enlarged rectangular opening topermit the projection of image light rays from the lens 21 to the mirror23. Similarly, the cabinet supporting the document plane is formed witha corresponding rectangular opening that mates with the opening in theprinter cabinet when the two cabinets are operatively joined togetherfor copy/duplicating purposes. Suitable light-type gaskets may beutilized adjacent the exterior of each opening in the cabinets in orderto minimize the leakage of unwanted extraneous light.

The xerographic belt 13 is mounted for movement around three parallelarranged rollers 27 suitably mounted in the frame of processor 11. Thebelt may be continuously driven by a suitable motor (not shown) and atan appropriate speed corresponding to the discharge responsive thephotoconductive material that comprises the belt and the intensity ofthe imaging light rays from the document. The exposure of the belt tothe imaging light rays from the document discharges the photoconductivelayer in the area struck by light whereby there remains on the belt anelectrostatic latent imaging of figuration corresponding to the lightimage projected from the document. As the belt continues its movement,the electrostatic latent image passes a developing station at whichthere is positioned a developer apparatus 29 for developing theelectrostatic latent image. After development, the powdered image ismoved to an image transfer station whereat record material or sheet ofpaper just previously separated from a stack of sheets 30 is heldagainst the surface of the belt to receive the developed powder imagetherefrom. The. sheet is moved in synchronism with the movement of thebelt during transfer of the developed image. After transfer, the sheetof paper is conveyed to a fusing station where a fuser device 31 ispositioned to receive the sheet of paper for fusing the powder thereon.After fusing of the powder image, the

sheet is conveyed through an opening in the cabinet to a finishingapparatus 32 for stapling or side stacking in a manner as will bedescribed more fully hereinafter. The sheets are separated from thestack and fed from the top of the stack by means of a separator rolldevice 33 and timed sequence of the movement of the I developed latentimages on the belt 13.

Further details of the processing devices and stations in the printersystem are not necessary to understand the principals of the presentinvention. However, a detailed description of these processing stationsand components along with the other structures of the machine printerare disclosed and copending application Ser. 7 Nos. 731,934, filed May24, 1968, and 756,598, filed Aug. 30, 1968, which are commonly assignedwith the present invention.

It will be appreciated that the printer system may be operated inconjunction with a roll converter unit indicated by the referencenumeral 35. The roll converter unit 35 is adapted to convert arelatively large roll of paper 36 into various sizes of sheets of paperby means of a cutter device 37 and a suitable control system (not shown)arranged to control cutting and feeding of the individual sheets intooperative cooperation with the separator roller 26. It will beappreciated that operative cooperation is assured between the variousunits operating with the printer system by the physical association ofthe cabinets for the units and the matching openings which enable fullcooperation of the imaging light rays and sheet transport path betweenthe units. In this regard, locking clamps may be provided on all theunits for preventing the inadvertent movement of such units during useand interlocks which is an alignment device may be utilized on each unitfor ensuring upper alignment and to terminate or suspend operation inthe event mis-alignment or separation of the units occur. For facilityand needs of operation, each of the units provided with caster wheelsand locking brakes thereby aiding in the movement of the units into andout of cooperative engagement.

FINISHING APPARATUS The finishing apparatus 32 comprises a frame 50having a main body housing 51 and cover 52 which is connected to theframe by rods 54 and 55 against the action of spring sets 57 and 59encircling the rods to secure the frame to the procesor 1 l aspreviously mentioned.

Finishing apparatus 32 includes an input receiving tray assembly 70, astapler group 72, a stapler head assembly 74, a side stacking assembly76 and an output receiving tray assembly 78. Input receiving trayassembly comprises an adjustable input receiving tray which serves toguide the sheet material along a path from the processor into thefinishing apparatus. The tray is adjustable for varying paper widthwhich may accept, as for example, 8 X 11 paper up to 9 X 14 paper.

The staple group assembly 72 comprises a registration gate 207 whichstops the forward motion of the sheet material, a paddle wheel 209 whichmoves the sheet to the forward left-hand corner of the input receivingtray for stapling by stapling head assembly 74 which drives staples intothe sheet material positioned on the receiving tray to produce finishedbooklets. For a detailed description of the stapling operation,reference is made to copending application 70,735, filed on even datewith the instant application and commonly assigned.

SIDE STACKING AND OUTPUT RECEIVING TRAY ASSEMBLIES Side stackingassembly 76 cooperates with output receiving tray assembly 78 to stacksheets in separately identifiable bundles instead of in stapled bookletsat the option of a machine operator. Tray assembly 78 includes a tray401 positioned at about a 7 W angle to the horizontal to facilitatereceiving sheets fed along the transport path. Tray 401 is mounted inthe frame for sliding movement in a vertical plane on slide shaft 403.The tray is lowered as the sheets are received to maintain a uniformlevel with the transport path by an elevator control system 404 as willbe described hereinafter.

The level of tray 401 is controlled by elevator control system 404.Elevator control system 404 includes a pair of lamps 450 and 451 andcorresponding phototransistors 453 and 454, respectively, and anassociated control circuit to be described including a reversible motorMOT 3. To move the tray the motor MOT-3 is energized to rotate a pulley457 which carries a cable 459 connected to slide shaft 403. On the downmovement during the side stacking operation, motor MOT-3 is onlyenergized in brief intervals to effect incrementally lowering the traydue to a braking action on the motor when power is shut 05. Levelcontrol is effected by signals received from phototransistors 453 and454 which provide signals to the control circuit when darkened. It willbe noted that lamps 450 and 451 direct a beam of illumination across thetop leading edge of the sheets toward their correspondingphototransistors. By this arrangement, the tray is caused to be lowereduntil such time as light is received by the photolransistors at whichtime power to motor MOT3 will turn off.

Side stacking assembly 76 serves to stack the sheets into shingled oroffset bundles on tray 401. The side stacking assembly comprises a pairof pivotable paddle wheels 415 and 417 which are similar in constructionto paddle wheel 209. Paddle wheel 415 has blade members 419, 420, and421 and paddle wheel 417 comprises blade members 423, 424 and 425.Paddle wheels 415 and 417 are mounted on a shaft 427 which is driven bya motor MOT-2 through the pulley 429 which receives a belt 431 which iswrapped around another pulley 433 mounted on the shaft 427. In thismanner, the paddle wheels 415 and417 are continuously rotated so thatthe blade members are advanced into contact with the topmost sheetreceived on tray 401 such that a sideways and ahead movement is impartedto the sheet as previously described in the case of paddle wheel 209.

Each of the paddle wheels 415 and 417 may be alternately positioned tocontact with the sheets advanced onto the tray depending upon whetherthe sheets of the topmost bundle are'to be stacked on the left of thetray. To accomplish this, the shaft 427 is supported in a frame 435which is suspended from a similar frame 437 on a pivot pin 439. Securedon one end of the frame 435. is actuating arrn 441 which is. connectedto a solenoid SOL-4. Upon receiving a signal as will be describedhereinafter, solenoid SOL-4 actuates arm 441 to cause the frame 435 topivot on pivot pin 439 so that paddle wheel 417 is in contactwith thesheets received onto the tray causing them to be stacked to one side. Atthe proper interval, solenoid SOL-4 is de-energized which causes frame435 to pivot due to the weight of motor MOT-2 and paddle wheel 415 to beplaced into contact with the oncoming sheets resulting in stackingtowards the opposite side. By repeating this sequence, offset stacks orbundles are formed of the sheet material received onto the tray.

MACHINE OPERATION An understanding of the machine operation of thefinishing apparatus may best be understood in connection with thecircuit diagrams in FIGS. 7 to 9 and the finishing apparatus controlpanel in FIG. 1 a. The processor has a control section for the finishingapparatus for selecting the mode of operation of the finishing apparatusin either the stapling mode or the side stacking mode. On the controlpanel are switches S10 and S11 for machine operator to select one of thetwo modes of operation. Also included in the control panel are indicatorlamps L10 and L11 to indicate when the finishing apparatus is in eitherof these modes of operation. A clear switch S12 is provided to enablethe finishing apparatus selection to be dropped if the processor is in astandby mode or if it is in a hold mode such as in the case of a jam.Also included on the control panel is a lamp L12 to indicate a jam hasoccurred at the finishing apparatus and a lamp L13 to indicate thateither of the input or output receiving trays is in a overflow conditionwith too much sheet material received therein. Another lamp on thecontrol panel L14 indicates that there is a misregistration between thepaper size of the processor and the finishing apparatus and also a lampL15 to indicate a low staple condition in the stapling head assembly.When the processor is turnedon the finishing apparatus receives powerthrough a relay K1. T0 actuate relay Kl power is received from a lowvoltage power supply 701 which serves to energize a coil to pull in acontact K1 of the relay K1 which allows power to be received by A/Cdrivers 705. The low voltage power supply 701 also provides power to D/Cdrivers 707 and a control logic 709 coupled to the D/C drivers. When thecontact Kl of relay K1 is closed, power is available to the eject motorMOT-1, paddle wheel motor MOT-4, the elevator motor MOT-3, the sidestack paddle wheel motor MUI2, the eject solenoid SOL-3, the side stacksolenoid SOL-4, the lamp drive transformer T2, and the transformer T1and bridge rectifier CR1 of the staple drive circuit.

In the stapling mode of operation, the staple switch S10 of the controlconsole is depressed. When the processor commences printing, controllogic 709 supplies a signal to a driver 705 which energizes a relay K2.Relay K2 energizes contact K2 which turns on motors MOT1, MOT-2, MOT-4,and transformer T1 and bridge rectifier CR1. When this occurs the copiesfrom the processor entering the finishing apparatus are received on theinput receiving tray and each copy contacted by the paddle wheel 209which then urges the copy sheet forward and to the left against theguide 107 and the registration gate 207. Succeeding copies are fed ontop of the preceding sheets by the paddle wheel 209 which is driven bythe motor MOT-4. When the last sheet of a stack is received in the tray,the control of the processor indicates that this condition exists to thecontrol logic 709 which then actuates a relay K3. When relay K3 isactuated, a staple driving circuit is turned on and the coil of thesolenoid SOL-3 energized which causes the stapling head assembly to beactuated into a stapling operation. When this occurs, a staple from thestaple roll is severed and fastened to the sheets. Relay K3 is thende-energized to de-energize the coil of the solenoid SOL-3 which returnsthe stapling head assembly to its rest position and at the same timeadvances the feed of the staple roll to position the next staple for thenext stapling operation due to the action of staple feed finger 357.When the staple head assembly starts to return to its rest position, thecontrol logic 709 provides a signal to a driver 711 which is coupled tothe gate solenoid SOL-1. When SOL-1 is energized, gate 207 is retractedin an upward position out of the path of the sheets. At the same time, asignal is provided to the coil of solenoid SOL-3 which is energized by adriver 721 which is energized by driver 723. When this occurs, ejectrolls 380 and 381 are actuated against the idler rolls 393, 394, toeject the stapled stack of sheets in a direction toward the outputreceiving tray 401. Exit rolls 390, 391 and idler rolls 396 and 397cooperate to maintain control of the sheets along its transport pathinto the receiving tray as they leave the eject rolls 380 and 381. Asthe stacks of sheets which are now stapled booklets are received by thereceiving tray 401, the tray is lowered incrementally to maintain thelevel of the topmost sheet on the tray at a predetermined height withthe transport path. Paddle wheel 415 contacts the stapled stacks to helpguide the sheets into the output receiving tray.

In order to ensure that the receiving tray 401 is lowered at the propertime intervals, there is a control circuit coupled to elevator motorMOT-3 which is energized when a coil of relay K4 is energized to pull ina contact K4. In order for the control logic 709 to provide a signal toa driver 727 for energizing relay K4 a signal is received from a sheetstacking sensing circuit 730 which includes phototransistors 453 and 454which receive illumination from lamps 450 and 451, respectively.Illumination from the lamps 450 and 451 is such as to impinge on thephototransistors 453 and 454 when the tray 401 is at the properelevation. Thus, the sheets start to collect, the path of illuminationis blocked and the resistance of the phototransistors increased. Whenthis occurs, an output signal is generated to operational amplifier 741which is set at a voltage level to provide an output signal to thecontrol logic 709. It will be noted that for this condition to occur,both of the phototransistors 451 and 453 must be blocked for aresistance increase to occur in both before and output signal is sent tocontrol logic 709. Desirably, lamp 451 is turned off during the staplingmode since the thickness of the staples on the same side assuresreliable operation with lamp 450 only. Motor MOT-3 has a brake whichnormally engages when power is not received as known by those skilled inthe art. in this manner, the movement of the tray is incremental toprovide a smooth reliable operation in a downward direction.

For a side stacking mode of operation, side stack switch S11 on thecontrol panel is pressed. When this occurs, the eject roll motor MOT-lis energized to rotate eject rolls 380 and 381 and the side stack motorMOT2 energized to rotate paddle wheels 415 and 417 through a closing ofa contact K2 which is caused when a a relay K2 is energized from controllogic 709. At the same time, a signal is received by the gate solenoidSOL-1 to pull the gate into an upward position out of the path of thesheets. At the same time, a signal is received by a relay K7 to close acontact K7 to energize eject solenoid SOL-3. As sheets are received inthe receiving tray 205, the sheets are advanced by the eject rolls 380,381 and the exit rolls 390 and 391 to feed the sheets directly to theoutput receiving tray 399. As the sheets are fed through the exit rolls,the sheets are driven sideways to the right by the side stack paddlewheel 417. A signal is received from the processor to control logic 709to cause a signal to be sent to a relay K8 which when energized closes acontact K8 to energize solenoid SOL-4 which, in turn, causes the sidestack paddle wheel 417 to be lowered into contact with the sheets andside stacked bundle commences. At the completion of the run, solenoidSOL-4 is de-energized and the side stack paddle wheel 415 lowered due toits weight into contact with the sheets causing the side stack paddlewheel 417 to be raised.

By continued actuation and de-actuation of the solenoid SOL-18 inaccordance with the control logic, the sheets received onto the outputreceiving tray are stacked to the left or to the right to form offsetbundles or stacks corresponding to the input information received by theprocessor. Tray 401 is incrementally depressed downwardly in the samemanner as described in connection with the stapling mode of operationexcept when stacking with paddle wheel 415, both lamps 450 and 451 areenergized. When stacking with paddle wheel 417, lamp 450 is energizedonly as in the case of the stapling operation for a more reliableoperation. Upon completion of a run in either the stapling mode or theside stacking mode, control logic 709 de-activates relay K2 which, inturn, opens a contact K2 to de-energize eject roll motor MOT-l, paddlewheel motor MOT-4 and the side stack motor MOT-2. At the same time, ifin the side stack mode of operation, relay K7 is de-energized to open acontact K7 to de-energize the solenoid SOL-1 for'eject rolls andsolenoid SOL-3 for returning the gate to a rest position.

A signal is then supplied to a solenoid SOL-5 which serves to releasethe cover 52 from its locked condition against the action of springs 57.It should be noted that when the cover solenoid SOL-5 is energized, thecover is released to a position slightly above the level of its normallyclosed position which then causes the solenoid SOL-5 to be de-energizedby control logic 709.

The machine operator then raises the cover 52 to its fully open positionclosing a switch S5 causing a relay K5 to be energized which closes acontact K5. When contact K5 closes, this energizes motor MOT-3 toreverse its drive and raise the tray 401 to its fully elevated positionin which the sheet material is brought directly upward to facilitate theremoval thereof from the finishing apparatus. When the tray 401 reachesits original starting position, the relay K5 is de-energized by thecontrol logic 709 to open contact K5 thereby deenergizing motor MOT -3.

JAM DETECTION J am detection is provided for in the control circuit by alevel detecting circuit 775 which serves to signal control logic 709when sheets are present in the vicinity of the gate 207. To accomplishthis, a lamp 777 is positioned in the sheet path to provide illuminationtoward a phototransistor 779 which is coupled to an operationalamplifier 781. When sheets are present in the sheet path, illuminationfrom lamp 777 is blocked and the resistance of phototransistor 779increased which causes the operational amplifier 781 to increase involtage resulting in a change in state on the output side of theoperational amplifier. When this happens, control logic 709 times out toindicate that a jam has occurred in the finishing apparatus and suppliesa signal to the processor to turn it off. Also, the control circuitincludes a low staple detect circuit 785 which serves to indicate to thecontrol logic 709 when a low staple condition has occurred in the staplehead assembly. To accomplish this, a lamp 787 is positioned to provideillumination to a phototransistor 789 when the staple roll shows nostaples are present which causes the resistance of the phototransistor789 to increase and the output condition of an operational amplifier 791to change which condition is indicated to the control logic 709.

Control logic 709 includes a counter for counting the sheets transportedalong the sheet path into the finishing apparatus so that an overflowcondition can be detected. When this occurs, a signal is supplied to theprocessor apparatus to indicate that an overflow condition exists toturn the processor ofl.

What is claimed is: v 1. Tray apparatus for stacking paper sheetmaterial comprising a tray member for receiving paper sheet materialtransported along a sheet path,

drive means including a reversible motor drivingly connected to saidtray member for lowering and raising thereof, and

cover means associated with said tray member voperative tomove from afirst position in which sheet material is received by said tray memberto a second position 1 after the sheet material is received, circuitmeans coupled to the drive means and cover means operative to actuatethe motor for lowering said tray member in response to discrete signalsfrom stack height sensing means to maintain the height of the sheetmaterial received level with the 10 sheet path and then to raise saidtray member to its original position in response to another signal toreverse the direction of said motor upon moving said cover means fromits first to its second position for unloading said tray member.

2. Apparatus according to claim 1 wherein said cir-' cuit means includesa plurality of sources of illumination each having an associated sensingdevice and spaced to effect sensing at different locations along theedge of the sheet material, and

wherein said circuit means includes means to cause operation of only aportion of the sources of illumination to achieve sensing at apredetennined location along the edge of the sheet material.

3. Apparatus according to claim 2 wherein said motor has a brakeassociated therewith to effect incremental lowering of said tray member.

4. Apparatus according to claim 3 wherein said tray member is inclinedfrom about 5 to about to the horizontal plane.

5. Apparatus according to claim 2 including stacking means associatedwith said tray member operative to move sheet material received therebyinto identifiable stacks.

. III l i i

1. Tray apparatus for stacking paper sheet material comprising a traymember for receiving paper sheet material transported along a sheetpath, drive means including a reversible motor drivingly connected tosaid tray member for lowering and raising thereof, and cover meansassociated with said tray member operative to move from a first positionin which sheet material is received by said tray member to a secondposition after the sheet material is received, circuit means coupled tothe drive means and cover means operative to actuate the motor forlowering said tray member in response to discrete signals from stackheight sensing means to maintain the height of the sheet materialreceived level with the sheet path and then to raise said tray member toits original position in response to another signal to reverse thedirection of said motor upon moving said cover means from its first toits second position for unloading said tray member.
 2. Apparatusaccording to claim 1 wherein said circuit means includes a plurality ofsources of illumination each having an associated sensing device andspaced to effect sensing at different locations along the edge of thesheet material, and wherein said circuit means includes means to causeoperation of only a portion of the sources of illumination to achievesensing at a predetermined location along the edge of the sheetmaterial.
 3. Apparatus according to claim 2 wherein said motor has abrake associated therewith to effect incremental lowering of said traymember.
 4. Apparatus according to claim 3 wherein said tray member isinclined from about 5* to about 10* to the horizontal plane. 5.Apparatus according to claim 2 including stacking means associated withsaid tray member operative to move sheet material received thereby intoidentifiable stacks.